Patent GB-1534428-A (GB)
Title: Cutting and insulation stripping apparatus for twisted wire pair
IPC: H02G1/12
Filed: 1976-08-13
Abstract: 1534428 Making wire lengths GARDNER-DENVER CO 13 Aug 1976 [9 Feb 1976] 33802/76 Heading B3A Apparatus for producing predetermined lengths of twisted wire pair with at least one end stripped comprises means to engage already twisted wire and feed forward a predetermined length, jaws to grip the wire, clamping means spaced from the jaws to clamp the wire and untwist the length between the clamping means and the jaws, wire and insulation cutting means operable on the untwisted wire section and means to move the cut ends relative to the insulation cutting means to strip the insulation from an end portion.  General arrangement.-The apparatus shown in Fig. 1 receives continuous, twisted wire pair 30 and issues predetermined lengths of wire pair with their conductors stripped of insulation at each end. As shown the twisted wire pair is fed from a reel through feed rollers 32, through a device 34 which detects splices in the wire and faults in the insulation, through a precisely indexable, and longitudinally movable wire feed device 26, and through a releasable clamp 36 to wire camming and positioning and wire and insulation cutting means 42, 40, 44. The wire then passes to a clamping and untwisting device 50 after which there is a tray 58 to receive the finished lengths. In operation wire is indexed through the apparatus, is clamped at 50, is clamped by a gripping device 130 preceding the point at which the wire is to be cut and the ends stripped and then the end clamped at 50 is rotated through a predetermined number of turns to untwist the wire to the required degree. The wires are then positioned, the wires cut, the insulation stripped and the length ejected. Wire positioning, cutting and stripping.-The arrangement comprises wire cutting blades (310, 312) Fig. 9, not shown, and on each side virtually identical mechanisms 42 and 44 to position the wires and strip insulation therefrom; only one of these mechanisms will be described. The mechanism 42, Figs. 12, 13, 15 and 16 comprises plates 220, 222 slidable towards each other in grooves under the influence of rods 118 which move towards each other as the wire cutting blades are operated. Wire camming and positioning plates 224, 226 and 228, 230 lie on either side of plates 220, 222 respectively, flanged bushings 232, 234 holding the cam plates on plates 220, 222. The cam plates are biased inwardly relative to plates 220, 220 by coil springs (244) Figs. 14, 15 not shown. Insulation cutting blades 254 are mounted on blade holders 250, 252 which are movable with rods 118. As rods 118 move towards each other after the wire has been untwisted, see Fig. 13, and the wires lie on a guide bar 120 cam surfaces 264, 266 on plates 224, 228, see Fig. 15, engage the wires and move them into a position such that a line joining their axes lies at 45 degrees to the vertical. Further movement of rods 118 causes these cams to release the wires and camming surfaces 268, 270 on plates 226, 230 to engage the wires and move them into positions, one vertically above the other, Fig. 17, not shown. Further movement of rods 118 causes a sloping surface 276, Fig. 13, on one of the blade holders 250 to engage the lower wire and move it upwards until both wires abut a projection on the holder 252 see Fig. 19. The wires are then correctly positioned to be engaged by recesses (272, 274) in the blade holders, Fig. 20, not shown, and finally the insulation is severed by the blades. The wire cutting blades sever the wire as the insulation is cut. The insulation cutting blades remain in their closed positions, gripping device 130 is opened and the clamp 36 and untwist unit 50 are moved away from each other while still gripping the wire to strip the insulation from the ends adjoining the cut. The untwist unit is then opened and an arms 200 remove the finished length and drop it in a tray 58. The mechanisms are operated pneumatically or by stepping motors under the control of a unit 60.